Various aspects of the present disclosure relate to base station antennas, and, more particularly, to diplexed antennas with semi-independent tilt.
Cellular mobile operators are using more spectrum bands, and increasingly more spectrum within each band, to accommodate increased subscriber traffic, and for the deployment of new radio access technologies. Consequently, there is great demand for diplexed antennas that cover multiple closely-spaced bands (e.g., 790-862 MHz and 880-960 MHz). Based on network coverage requirements, operators often need to adjust the vertical radiation pattern of the antennas, i.e., the pattern's cross-section in the vertical plane. When required, alteration of the vertical angle of the antenna's main beam, also known as the “tilt”, is used to adjust the coverage area of the antenna. Adjusting the beam angle of tilt may be implemented both mechanically and electrically. Mechanical tilt may be provided by angling the diplexed antenna physically downward, whereas electrical tilt may be provided by controlling phases of radiating signals of each radiating element so the main beam is moved downward. Mechanical and electrical tilt may be adjusted either individually, or in combination, utilizing remote control capabilities.
Network performance may be optimized if the tilt (e.g., electrical tilt) associated with each frequency band supported by an antenna is completely independently controlled. However, this independence may require a large number of diplexers and other components, adding significant cost and complexity to the creation of a diplexed antenna.
Accordingly, it would be advantageous to have a low complexity, cost-effective diplexed antenna able to produce high quality radiation patterns for each of the supported frequency bands.